The present invention relates to a liquid crystalline polyester resin composition for a connector.
A liquid crystalline polyester resin is excellent in melt fluidity and heat resistance since its molecules are so rigid that it is not to be entangled even in the melted state and its molecular chains are remarkably oriented in the flow direction by shearing at the time of molding and are kept in the oriented state even at the time of solidification.
Therefore, a molded article obtained by using a resin composition containing a liquid crystalline polyester resin mixed with fibrous reinforcing materials such as glass fiber, inorganic fillers such as talc, and the like has been preferably used for applications to electronic parts such as connectors having thin portions and complicated shapes. However, along with the advancement of surface mounting technology and the preference of lightness, thinness, shortness, and compactness of mobile appliances such as a mobile phone and the like, the requirements for connectors to be made thin and suppressed from warping have become intensive. In order to make connectors thin and suppressing warpage of molded article, various investigations regarding fillers to be mixed have been carried out.
For example, JP10-219085A discloses that use of a resin composition containing a resin mixture obtained by mixing two types of liquid crystalline polyesters having different flow beginning temperatures and inorganic fillers makes it possible to produce connectors excellent in the fluidity at the time of molding and having suppressed its warpage.
However, since connectors are required to be extremely thin, it has been desired to develop a resin composition that has further improved fluidity at the time of molding and is therefore capable of producing connectors with further suppressed degree of warpage.
The object of the present invention is to provide a liquid crystalline polyester resin composition for connectors that is excellent in fluidity at the time of molding and is therefore capable of producing connectors with further suppressed degree of warpage.
Inventors of the present invention have enthusiastically made investigations to find a liquid crystalline polyester resin composition for connectors free from such problems described above and consequently found that a resin composition obtained by mixing an inorganic filler with a mixture of liquid crystalline polyester resins obtained by acylation, ester exchange or both acylation and ester exchange in the presence of a heterocyclic organic basic compound having two or more nitrogen atoms is excellent in fluidity at the time of molding and has suppressed degree of warpage of a molded article and therefore is suitably applicable to connectors and finally inventors have completed the invention.
That is, the present invention provides a liquid crystalline polyester resin composition for connectors comprising 100 parts by weight of a liquid crystalline polyester resin mixture which comprises 100 parts by weight of a liquid crystalline polyester (A) having a flow beginning temperature of from 300xc2x0 C. to 400xc2x0 C. and from 10 to 150 parts by weight of a liquid crystalline polyester resin (B) having a flow beginning temperature of from 260xc2x0 C. to 350xc2x0 C. and the difference between the flow beginning temperature of the liquid crystalline polyester resin (A) and the flow beginning temperature of the liquid crystalline polyester resin (B) is from 20xc2x0 C. to 60xc2x0 C., and from 15 to 180 parts by weight of a fibrous and/or plate-shaped inorganic filler; wherein both of the liquid crystalline polyester resin (A) and the liquid crystalline polyester resin (B) are produced by ester exchange reaction between at least one selected from a group consisting of aromatic dicarboxylic acids and aromatic hydroxycarboxylic acids, and an acylated compound obtained by acylation of phenolic hydroxyl group of at least one selected from a group consisting of aromatic diols and aromatic hydroxycarboxylic acids with a fatty acid anhydride, and at least one of the acylation and the ester exchange reaction is carried out in the presence of a heterocyclic organic basic compound having two or more nitrogen atoms.